1. Field of the Invention
The present invention relates to an actinic ray-sensitive or radiation-sensitive resin composition, in particular, an actinic ray-sensitive or radiation-sensitive resin composition for use in the process of producing a semiconductor such as IC, in the production of a circuit board for liquid crystal, thermal head and the like or in other photo-fabrication processes, and a pattern forming method using the same. More specifically, the present invention relates to a positive chemical-amplification resist composition suitable for exposure using a light source that emits a far ultraviolet ray at a wavelength of 250 nm or less, preferably 220 nm or less, or an electron beam, and a pattern forming method using the same.
2. Description of the Related Art
As for the actinic ray-sensitive or radiation-sensitive resin composition such as chemical amplification resist composition used in the photolithography process of a semiconductor or the like, particularly, in the case of using an ArF excimer laser (wavelength: 193 nm) as a light source, a resin having an alicyclic hydrocarbon group is used from the standpoint of transparency and dry etching resistance.
The actinic ray-sensitive or radiation-sensitive resin composition containing a resin having an alicyclic hydrocarbon group requires a stronger acid, and a compound capable of generating a perfluoroalkylsulfonic acid, such as triphenylsulfonium trifluoromethanesulfonate, is used.
The perfluoroalkylsulfonic acid is, however, highly hydrophobic, and an actinic ray-sensitive or radiation-sensitive resin composition using an acid generator capable of generating this acid is reduced in the affinity for an aqueous developer, which gives rise to a problem such as reduction of sensitivity due to worsened developability or generation of development defect.
To solve this problem, JP-A-2007-155925 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”) describes a photosensitive composition using a compound capable of generating a specific acid containing a fluorine atom.
However, with further refinement of a pattern, more improvements of various performances particularly in terms of exposure latitude and line edge roughness are demanded.
Also, a resin containing a specific lactone structure is disclosed in JP-A-2001-188346 with an attempt to improve the development defect.
Along with miniaturization of a semiconductor device, the trend is moving into a shorter wavelength of the exposure light source and a higher numerical aperture (higher NA) of the projection lens, and there is known a so-called immersion method of filling a high refractive-index liquid (hereinafter sometimes referred to as an “immersion liquid”) between the projection lens and the sample so as to raise the resolution by more shortening the wavelength. The immersion method is effective for all pattern profiles and furthermore, can be combined with the super-resolution technology under study at present, such as phase-shift method and modified illumination method.
However, it is pointed out that when the chemical amplification resist is applied to immersion exposure, the resist layer comes into contact with the immersion liquid at the exposure, as a result, the resist layer deteriorates or a component adversely affecting the immersion liquid bleeds out from the resist layer. International Publication No. 2004/068242 describes a case where when a resist for ArF exposure is dipped in water before and after exposure, the resist performance is changed, and this is indicated as a problem in the immersion exposure.